I just noticed that two Paizo products that I did a lot of writing for are both coming out on the same day. The Giant Hunter's Handbook was a lot of fun, and required finding design space for a lot of mechanics (feats and so on) as well as learning a lot about giants in the game--what their commonalities are, how big they are in relation to each other, and so on. Lost Treasures also required a lot of mechanics--as I created about half of the items in this book--but it also allowed me to do a lot of worldbuilding as well. In all, Lost Treasures is probably some of the most enjoyable RPG writing I've done.